1. Field of the Invention
The present invention relates to a two-component developer used for the development of a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method or the like.
2. Discussion of the Related Art
During durablity printing in a high-speed machine or durability printing in a low toner-consumptive mode, such as a long-term printing of fixed images in a low printing ratio, fixed images are likely to be deteriorated due to a decrease in image density and the like with the embedment of silica. Therefore, there has been proposed to use a toner in which an external additive having a large particle size is used (Japanese Patent Laid-Open No. Hei 6-332253), or to use a carrier having a low saturation magnetization. However, the decrease in image density, the background fogging, the toner scattering, the carrier sticking on photoconductor and the like may be caused.
An object of the present invention is to provide a two-component developer which can continuously give high-quality images, even in a high-speed machine, without causing the embedment of silica and the carrier sticking on photoconductor.
The present invention relates to a two-component developer comprising:
a toner onto which a hydrophobic silica having an average particle size of 25 nm or more is externally added, and
a carrier having a saturation magnetization of from 50 to 95 Am2/kg, wherein the carrier has a ratio of surface resistivity to volume resistivity of from 1xc3x97102 to 1xc3x97104 mxe2x88x921 at an electric field strength of 100 V/cm.